1. Field of the Invention
The present invention relates to a printing apparatus provided with a paper ejecting mechanism for ejecting a printed paper to mutually different paper ejecting positions and a printing method for the printing apparatus, and more particularly, to the paper ejecting position control method and apparatus of the printing apparatus as described above designed to carry out the paper ejecting position control so that the proper recovery can be performed at the time of the occurrence of a printing failure.
2. Description of the Related Art
With the development of the high performance printer apparatuses, there have frequently been practiced to print a plurality of different kinds of documents with a series of print information. In order to sort different kinds printed documents, a paper ejecting mechanism is used which is designed to give the so-called offset of the paper ejecting position by document to the paper ejected from the printer apparatus.
On the other hand, the requirements for an elevation of reliability of a computer system have become higher year by year, and high reliability is demanded for the printer apparatuses with respect to its printing results. For example, in case of a printing failure caused by stoppage of the printer apparatus due to paper jamming or paper shortage during the use of the printer apparatus, assured and easy practice of recovery (re-printing) is required so as not to cause excess or shortage to the printing results including the offset position.
With respect to the conventional paper ejecting position control method, description is made in reference to FIG. 1 and FIG. 2 which show the conventional printing system 1 and printing apparatus 4.
In FIG. 1, the printing apparatus 4 comprises a print control unit 11 and a printing portion 12. To the print control unit 11, print information DP is inputted where the print information DP is transmitted from an upper rank apparatus 3. The print information DP includes the printing information DT which is the printing contents and attribute information DA of the printing information DT. The attribute information DA includes offset information DF which is information to instruct the paper ejecting position. The printing portion 12 has a printing mechanism 31 for performing printing on paper according to the contents of the printing information DT and a paper ejecting mechanism 32 for ejecting the printed paper to the ejecting position instructed by the offset information DF.
The offset information DF is allocated in units of a page to be printed, and information to show whether or not each page should be placed in the different paper ejecting position from the preceding page, i.e., whether or not there is a request to give an offset (offset request). The print control unit 11, when it has received the information of "offset request yes", stores. the offset information DF in a paper information table 26 provided for the internal administration of the print control unit 11. When sending a request for printing of said page from the print control unit 11 to the printing portion 12, the print control unit 11 issues an instruction containig the offset position to the printing portion 12 immediately before the request for printing.
When issuing an instruction containig the offset position from the print control unit 11 to the printing portion 12, the offset position is determined on the bases of the offset information DF stored in the paper information table 26 and the contents of the instruction evacuating area 24. According to the determined offset position, i.e., the offset position for which the actual instruction has been issued, the contents of the instruction evacuating area 24 are updated.
Next, regarding the conventional offset position instructing condition and recovery condition when printing failure, a concrete description is made based on FIG. 3, FIG. 4, and FIG. 5.
FIG. 3 is a view showing the conventional state of the case of printing by the print information DP1 for five pages and ejecting the paper by offsetting on the fourth page; FIG. 4 is a view for illustrating the conventional condition of instructing the offset position; and FIG. 5 is a view for illustrating the conventional condition of the offset position in a recovery.
In FIG. 3A there are shown on the first page and the fourth page the conditions to which the information of "offset request yes" is attached. In FIG. 3B, there is shown the paper ejecting condition in the case where proper paper ejection is made based on the print information DP1.
In FIG. 4, since the first page is "offset request yes", prior to the request to print the first page, the offset position is contained in an instruction from the print control unit 11 to the printing portion 12. In the contents of the instruction evacuating area 24, the initial value is "0", so that based on this and "offset request yes", "X position" is determined as the offset position and instructed. Together with the instruction of "X position", the contents of the instruction evacuating area 24 are updated to "X position". In the printing portion 12, the "X position" is memorized as the paper ejecting position of the first page. Subsequently, each printing information DT of the first page, second page, and third page is sent from the print control unit 11 to the printing portion 12.
Because the fourth page is "offset request yes", prior to the request to print the fourth page, the offset position is contained in an instruction to the printing portion 12 from the print control unit 11. The contents of the instruction evacuating area 24 is "X position", and based on this and "offset request yes", "Y position" is determined as the offset position and instructed. Along with the instruction of "Y position", the contents of the instruction evacuating area 24 is updated to "Y position". In the printing portion 12, "Y position" is memorized as the paper ejecting position of the fourth page. Thereafter, each printing information DT of the fourth page and the fifth page is sent from the print control unit 11 to the printing portion 12.
Subsequently, or in parallel with it, printing is performed in the printing portion 12, and paper ejection is made in order of the first page, second page, and third page to the "X position". Offset is made next, and the fourth page and fifth page are ejected to the "Y position". As a result, the printed paper is ejected under the condition shown in FIG. 3B. This is a normal condition.
However, conventionally, in case paper jamming occurs in paper ejection during printing or after printing, the printing is operated normally by recovery, but the paper ejection fails to be in a normal condition.
Therefore, in FIG. 5, the request for printing from the first page to the fifth page and the instruction of the offset position progress in the same manner as described in FIG. 4. There is assumed the case where, after the printing, the first page paper ejection is normally performed in "X positions", then paper jamming occurs.
When paper jamming occurs, according to the processing of its recovery, the printing information DT memorized in the printing portion 12 is erased, therefore, by the recovery processing, the printing information DT on and after the second page is re-transmitted from the print control unit 11 to the printing portion 12. On such occasion, providing an instruction containing the offset position is performed prior to the request for the printing of the fourth page. In such a case, because the contents of the instruction evacuating area 24 is "Y position", "X position" is determined as the offset position and instructed.
Therefore, notwithstanding the fact that the fourth page is required to be ejected to "Y position", "X position" is instructed, and all pages from the first to the fifth page are ejected to "X position". As a result, the printed paper is ejected without being offset as shown in FIG. 3C, providing a condition that the divisional point of the document is unclarified.
Furthermore, during printing by the print information DP2 accompanied with the offset request, interruption may be made by printing by other print information DP3. In such a case, due to the presence of the latter interrupting print information DP3, the offset position of the original print information DP2 may be affected, and the paper printed under the original print information DP2 may not be ejected to its proper position.